1. Department of General, Visceral, and Transplantation Surgery, Charité Campus Virchow Universitätsmedizin Berlin, 13353 Berlin, Germany
2. Department of General and Visceral Surgery, Bielefeld Evangelical Hospital, 33617 Bielefeld, Germany
3. Department of Hematology/Oncology, Comprehensive Cancer Center, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany
4. Department of Biostatistics, Coordination Center for Clinical Trials, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany